Joseph banks davies



2 sheets-s'neet 1.

(No Model.)

y J. D. DAVIES.

PUMP..

No. 315,485. Patented Apr. 14, 41885 WIT/VESSES me Model.) 2sheetsTsneen 2.

' J. D. DAVIES.

. PUMP. N0. 315,485.

R 0 T N rE V N l N PETERS. Phawunwgnpher. wa-hington. 0.a

5. 8 .w u. w... A. ,1w ,m ...w D'.

WIM/8858 UNITED STAT-IISN JOSEPH BANKS DAvInS, or NATCHEZ, MISSISSIPPI.

PATENT FPICE.

PUMP. f

SPECIFICATION forming part of Letters Patent No. 315,485, dated April14, 1885. V'

Application mea May 1`, 1884. (No moda.)

To all whom it may concern:

Be it known that I, JOSEPH DANKS DAvII-Is, of Natchez, in the county ofAdams and State of Mississippi, haveinvented certain new and usefulImprovements in Pumps; and I do hereby declare the following to be afull, clear, and exact description of the invention, such `as willenable others skilled in the art to which it appertains to make and usethe same.

My invention relates to an improvement in pumps, the object of the samebeing to provide a pump which shall be differential-viz., one in whichthe amount of work accomplished shall be proportional to the pressure orhead, thus enabling the engine to drive it'against any load, a furtherobject being to prevent shocks from taking place in the pump from suddenchanges of pressure either on the in-4 let or exit side of the piston.

` With these ends in view my invention consists in certain features ofconstruction and combinations of parts, as will be fully described, andpointed out in the claims.

In the accompanying drawings, Figure 1 is a view in verticallongitudinal section through the pump and cushion-cylinder. Figs. 2 and3 are views showing springs employed in place of the fluid or aircushion cylinder. Fig. Ltis a view in vertical section of the pump,showing two cushion-cylinders connected thereto. Fig. 5 is a view on theline x .fr of Fig. 4.-; and Fig. 6 is a view on the line y y of Fig. 5,the pipe O, which is omitted in Fig. 5, being shown. t

a represents apump-cylinder tted as usual with a piston or plunger,B,which is attached to an operating-rod, A.' c is another vcylinder ofany approvedfsize, situated conveniently in close proximity to andparallel'with the cylinder a. The cylinders a and a communicate witheach other at both ends. The cylinder a is provided with a piston, B. Athird cylinder, a2, is preferably situated longitudinally opposite thecylinder a, and rigidly secured thereto by means of bolts n or othersuitable means. The cylinder a is provided with a-piston, BZ, the latterbeing connected with the piston B by a connecting-rod, b, passingthrough the adjacent ends of the cylinders a' and a2, which ends of the.cylinders are held a sufficient distance apart to admit the properstuffing-boxes. The cylinder a is the cylinder a.

provided with the exit-valves c c, and the cylinder a withtheinletvalves d d. rlhe cylinder a2, which may be conveniently termed thecushion-cylinder, is p rovided with the inlet-valves e e' and with thesafety-valves F y, F. f The cylinder a is further provided with thefeed-pipes H H', one of which may conveniently feed liquid and the othergas or 6o steam.

The operation of the pump is as follows: Supposethevalvcs c c d d e e FF to be closed, the cylinders a apfull of water, and the cylindergiglledwith air, gas, steam, liquid, or a mixture of liquid and air or gas. Let

' the three pist'ons be in the position shown in Fig. l. Suppose, now,power to be applied to the rod A, forcing the piston B in the directionShown by the arrow. The piston B 7o will be thereby forced intheopposite direction, and will carry with it the piston B2 in The air notbeing able to escape from a2 until the pressure is sufficiently great tolift/the safety-valve, the piston `B2 75 will accumulatepressure beforeit and tend to produce 'a vacuum behind it until the said piston nearlyor quite comes "to a standstill, when the pressure beforethe piston B ina will'become sufcientlystrong to lift the exit- 8o valve c and'deliverwater therefrom. AtA this same moment there is produced a suffI- p cientvacuum behind the piston B `to open the inlet-valve d', 'which nowadmits water.

B now starts on its return. force of the gas or air,com`pressed by theprevious motion of the piston B2 will now be given back to the piston B.As the piston B'z moves in the return motion, the air in the c linder a2is again com ressed beforeit and 9a Y s P a partial rvacuum formedbehind it until it again comesvto a standstill. J ust before it` comesto a rest, the pressure in the cylinder a becomes sufciently great toopen the valve c',

and water is delivered at the same moment 95"" the valve d is opened bythe partial vacuum formed, and water enters the pump.` `Vhen the pistonB2 arrives atmid-stroke, it is in equilibrium as far as the pressure inthe cylinder ai is concerned, `but will continue to loo move on accountof its own momentum and the pressure on the piston B until the com"pressed air before it causes it to stop.

The dropping of the valves c c may take .The expansive f place as soonas the pistons B and B2 stop, or as soon as the return motion of thepiston B releases the pressure and allows the air in a2 to regain itsequilibrium.

t' represents an air-chamber in connection with the cylinder c. It isprovided with a cut-off valve, K, to shut the air in the chamber oft`from the cylinder a whenever desired. It is found advantageous to dothis when starting the pump. The air-chamber i may or may not be used inconnection with the cylinder, or there may be two air-chambers, one ateach end of the cylinder.

There may be cut-oft` valves also, arranged between the cylinders a anda to throw the latter out of communication with the former Wheneverdesired.

As before stated, the pipes H H may lead gas and liquid, respectively.Now, it is obvious that the more liquid in combination with the gas theless will be the movement of piston B2, the pressure from piston Bremaining constant. Again,the curve of force transmitted may be variedby either of the following methods-viz., first, by increasing thepressure; secondly, by changing the relative sizes of the cylinders aa2; and, thirdly, by the amount of clearance in a2. These severalchanges give results represented by different portions of the hyperboliccurve of expansion of gases. It will be seen,therefore, that differentpressures required to pump against cause different sweeps of piston B',thereby causing the amount of delivery to be in proportion to thepressure.

In place of the expansion of gases a spring may be used in the cylindera2, as shown in Figs. 2 and 3. Vith straight connections the effect willnow be invariable; but if a'volute or elliptic spring, S, be used, asrepresented, and the center connection,B2,be made so that it can movemore or less before catching the spring S,the differential will bemodified.

In Figs. 4, 5, and 6 the cushion-cylinder is made in two parts, f f,pivoted to a suitable frame by its hollow trunnions o. Each cylinder fis provided with a piston and pistonrod, the outer ends of which latterare connected by the iianged collar t to the rod b. The hollow trunnionsof both of these pistons are connected tothe steam, air, or water supplypipe O, provided, preferably, at a point outside of both hollowtrunnions with a checkvalve, o', adapted to prevent the escape orbackliow of the gas or water. The ports o2 of the hollow trunnionsterminate at or near the inner or adjacent ends of the cylinders f, soas to admit the actuating-fluid in front of both pistons. When thepistons are in equilibrium, as shown in Figs. 4 and 5, the pistons ofthe cylinders f rest at the limit of their outward movement. As soon,however, as Vthe pressure in the cylinder c is sufficient to move thepiston B in either direction, both cylinders turn on their trunnions,andthepistons thereof are drawn toward the inner or adjacent ends of theirrespective cylinders and form the cushions.

It is evident that numerous slight changes in the construction andrelative arrangement of the several parts might be. resorted to withoutdeparting from the spirit of my invention, and hence I would have itunderstood that I do not conline myself to the exact construction shownand described, but consider myself at liberty to make such changes asfairly fall within the spirit and scope of my invention.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. In a pump, the combination,with a main cylinder having outlet-valvesand a piston,V

and an auxiliary cylinder provided with a piston and supply-valves incommunication with the main cylinder, of a cushion-cylinder connectedwith the piston in said auxiliary cylinder by a piston-connecting rod,substantially as set forth.

2. In a pump, the combination,with a main cylinder having outlet-valvesand operatingpiston, and an auxiliary cylinder in communication with themain cylinder and provided with a piston and supply-valves, of acushioncylinder having its axial line on the prolongation of the axialline of the said auxiliary cylinder, said cushion-cylinder beingconnected with the auxiliary cylinder by an independent pistonconnectingrod, substantially as set forth.

3. In a pump, the combination,with a main cylinder having outlet-valvesand an operating-piston, and an auxiliary cylinder provided withsupply-valves and a piston in communication with the main cylinder, of acushioncylinder provided with valves for admitting air, gas, or liquid,and a rod connecting the piston in the auxiliary cylinder with a pistonin the cushion-cylinder, substantially as set forth. y Y

4. In a pump, the combination,with a main cylinder having outlet-valvesand an operating-piston, and an auxiliary cylinderI having supply-Valvesin communication with the main cylinder, of a cushion-cylinder providedwith check-valves for alternately admitting and preventing the escape ofair, gas, or liquid, and further provided with safety-valves and a rodconnecting a piston in the auxiliary cylinder with a piston in thecushioncylinder, substantially asset forth.

5. In a pump, the combination,with a main and auxiliary cylinder havingtheir axial lines parallel and communicating directly with each other,the main cylinder being provided with a piston and two delivery-valves,and the auxiliary cylinder with two supply-valves, of a cushion-cylindersituated longitudinally opposite the auxiliary cylinder, and a rodconnecting a piston in the auxiliary cylinder with a piston in thecushion-cylinder, substantially as set forth.

6. In a pump, the combination,with a main IOO IIO

315,485 K V l if fr cylinder provided with suitable supply andspecification inthe presence of two snbserilo` delivery valves andoperating-piston, of one ing Witnesses. l

or more air-chambers communicating with the 4 main cylinder, and devicesfor shutting off the JOSEPH BANKS DAVIEST 5 air-chambers from thecylinder at pleasure, Witnesses: substantially as set forth. W. B.PRINCE,

In testimony whereof I have signed this WALTER MCCREA.

